We know that the Weasleys keep chickens, but that's the most intensive bit of animal husbandry we've seen in the series. Though Hogwarts has large greenhouses, the plants grown are used for magical purposes, and not for consumption.
So the question is, where does the wizarding world get its food from? Since Gamps' Law states that food cannot be conjured, there has to be wizarding farms of some sort, but how large and numerous do you think they would be? Or would wizards just get food from Muggle sources?
Also, concerning Gamp's law, you can't create food out of nothing, but Hermione says you can increase the quantity with magic. Wouldn't that be something of a contradiction? You could just get one piece of food and duplicate it indefinitely, at which point you are pretty much just creating food purely by magic.
Tim the Enchanter